Intravitreal Injection of AAV Expressing Soluble VEGF Receptor-1 Variant Induces Anti-VEGF Activity and Suppresses Choroidal Neovascularization

Abstract

PURPOSE. With anti-VEGF-based treatments for wet AMD requiring frequent injections, it is often burdensome to both patients and healthcare providers. To explore its possibility as a desirable alternative, we investigated the therapeutic potential of a recombinant adenoassociated virus 2 expressing a soluble variant of VEGF receptor-1 (rAAV2-sVEGFRv-1) in a laser-induced choroidal neovascularization (CNV) model, as CNV is a defining feature of AMD progression. METHODS. C57/B6 mice were intravitreally administered with rAAV2-sVEGFRv-1, rAAV2-GFP, or clinically used bevacizumab after CNV lesions were induced via laser photocoagulation. Immunostaining was performed with phalloidin and CD31 to measure CNV extensiveness, F4/80 and CD11b for inflammatory cell infiltration, and pan-cytokeratin to visualize fibrotic progression. RESULTS. rAAV2-sVEGFRv-1 (5.0 3 10 7 viral genomes) possesses antiangiogenic, antiinflammatory, and antifibrotic properties. rAAV2-sVEGFRv-1 was demonstrated to significantly decrease retinal CNV lesion size (1336 6 186) when compared to rAAV2-GFP-treated (2949 6 437, P ¼ 0.0043), mock-treated (3075 6 265, P ¼ 0.0013), and bevacizumab-treated models (995 6 234). Infiltration by inflammatory cells significantly decreased with rAAV2-sVEGFRv-1 administration, while groups treated with rAAV2-GFP did not. Additionally, antiapoptotic activity was observed via TUNEL assay in rAAV2-sVEGFRv-1 (16.0 6 3.6) and rAAV2-GFP (46.0 6 7.5, P ¼ 0.003). Overall, the rAAV2-sVEGFRv-1 viral vector was positively comparable to bevacizumab, indicating it as effective as approved therapeutics. CONCLUSIONS. The ability of a low dose of rAAV2-sVEGFRv-1 to exert a therapeutically relevant anti-VEGF effect in a CNV model is demonstrated, and strongly suggests gene therapy as an effective and convenient treatment for sustained VEGF suppression.

Intravitreally Administered Soluble VEGF Receptor-1 Variant Tested as a Potential Gene Therapeutic for Diabetic Retinopathy

“…As a result, sFLT-1 is able to exert anti-VEGF effects via multiple mechanisms. The antiangiogenic activity of rAAV2-sVEGFRv-1 could be seen in our previous work [18], where it was demonstrated in a laser-induced mouse model of choroidal NV, among other effects.…”

“…As such, we initially explored the therapeutic potential of intravitreally injected rAAV2-sVEGFRv-1, its antiangiogenic activity in particular, in a laser-induced mouse model of choroidal NV, an animal model system for the wet subtype of age-related macular degeneration (wAMD) [18]. There, it was shown to reduce the extent to which choroidal NV occurred at levels comparable to bevacizumab, in addition to being antiapoptotic and reducing inflammatory cell infiltration.…”

“…Virus Vector Development. rAAV2-sVEGFRv-1 and rAAV2-GFP were prepared as previously described [18]. Briefly, the region spanning nucleotide positions 282 to 2,253 of the mRNA for human VEGF receptor-1 (XM_ 017020485.1; NCBI Reference Sequence, NIH) was inserted into a rAAV2 vector under the control of a CMV promoter along with a SV40 polyadenylation signal and both ITRs to produce rAAV2-sVEGFRv-1.…”

Viral-Vector-Delivered Anti-Angiogenic Therapies to the Eye

“…Pathological angiogenesis can be inhibited via soluble VEGF receptors [74]. In a study, intravitreally injected AAV2 expressing a soluble variant of VEGF receptor-1 decreased CNV lesion size 14 days after laser induction in the laser-induced CNV mouse model.…”

Viral-Vector Delivered anti-Angiogenic Therapies to the Eye

“…Pathological angiogenesis can be inhibited via soluble VEGF receptors [51]. In one study intravitreally injected AAV2 expressing a soluble variant of VEGF receptor 1 decreased CNV lesion size 14 days after laser induction in the laser induced CNV mouse model.…”